Railcars and trucks or cabs having trailers can have open-top trailers or containers, for which the contents may want to be protected from the environment or local regulations may require to be covered while transporting such contents of the container. Many truck trailers and rail cars, particularly those hauling loose loads, such as sand and gravel, need a cover to prevent the wind from blowing contents from the container. Trucks and rail cars having open-top container cars may have covering systems. Thus, open-top containers often have tarp systems to cover the contents. Tarps are well known for covering contents of a container of the trailers and railcars during transport. Tarp covering systems are preferably automated to cover trailers or containers while transporting contents of the container. But size limitations and effectiveness must be maximized for covering systems.
U.S. Pat. No. 6,257,646, the disclosure of which is incorporated by reference, discloses an apparatus 10 including a sliding pivot for moving a cover over a bed 12 of a truck 14. The apparatus 10 comprises a pair of rails 16, a pair of bows 18 and a pair of cylinders 20. Each bow 18 has a first end connected to a cover and a second end connected to a follower adjustable along an associated rail. The cylinders are connected to an associated follower, and develop a force along a plane defined by the rails to slide the followers along the rails. The bows are slideable and pivotable to move the cover over the bed of the truck from a retracted position proximate a front end of the bed to an extended position proximate a rear end of the bed. The lower end 40 of the bow 18 pivotably cooperates with an outer rail 36 via a hinge 44 as described in U.S. Pat. No. 5,887,937. The pivot mounting apparatus may include a housing, a pivot assembly, a locator pin, and at least one spiral torsion spring. The springs are in the housing and engage or otherwise cooperate with the locator pin and axial groove in a shaft to bias the pivot assembly toward a home position. A hydraulic circuit used with cylinders with pistons and valves are disclosed in U.S. Pat. No. 6,659,531. A raiseable tower 22 is preferably also included. Since these patents, truck frames and fenders have become wider to limit the available space outside of the fender.
Intermediate mounting between the fender and container of a truck was possible, but narrower components are now needed.
Various other apparatus have been devised for covering a trailer load. Some such apparatus particular for container trucks, such as for the waste market, include a motor for selectively winding a flexible cover. An effective cover should be one that is easily operated so as to selectively cover and uncover the load from the convenient location of the truck cab. U.S. Pat. No. 5,031,955 provides a truck cover that may be conveniently motor operated from the cab of a truck to extend the cover from a winding assembly proximate the front of the truck bed and toward the rear of the truck bed. The truck cover assembly 20 includes a flexible cover 22, a winding assembly 24 for winding and storing a cover 22, an extension assembly 26 for extending a cover 22 over load bed 14, and a tension assembly 28 for applying a downward force on cover 22 proximate front end 16 of load bed 14.
Another refuse tarping system is RP4500SAR of Pioneer, a Wastequip company. It includes telescoping low arms, but it uses a rack and pinion system. This rack and pinion system may be installed on a two-and-a-half inch square tube mounted to the side of a truck. With a rack mounted with teeth facing up, debris can get jammed between the rack and pinion. A wedged stone can lock up a rack and pinion system. Typically, such a system is hydraulically driven in both directions. Other tarping systems may use concentric springs to bias a system in one direction.
Within the context of container truck cover systems, the tarping system must operate within strict dimensions. For example, a knuckle, rack and pinion, or pivot assembly may have to operate in a width that is only three inches wide. A maximum fender width and container width allowed by U.S. regulations is 102 inches. The maximum width allowed for a tarping system is 108 inches, which leaves three inches per side that may be unobstructed for the covering system to mount and operate.